Knowledge of coronary vein anatomy is becoming increasingly important for diagnostic and interventional cardiac procedures including epicardial radiofrequency ablation, retrograde perfusion therapy in high-risk or complicated coronary angioplasty, arrhythmia assessment, stem cell delivery, coronary artery bypass surgery and cardiac resynchronization therapy (CRT). Congestive heart failure currently afflicts over 5 million Americans. In patients with severe congestive heart failure, CRT has been proven as an adjuvant therapy to pharmacological treatment. In CRT, simultaneous pacing of the right ventricle and left ventricle, or pacing the left ventricle alone, results in hermodynamic improvements and restoration of a more physiological contract pattern. One of the technical difficulties of CRT is in achieving effective, safe and permanent pacing of the left ventricle. Three methods have been proposed for implantation of a pacemaker lead in the left ventricle: (I) an epicardial route via thoracotomy, (II) left ventricle endocardial pacing via trans-septal catheterization, and (III) transvenous implantation through the coronary sinus using an available posterolateral coronary vein branch. Transvenous coronary sinus pacing is the most common technique as it has the least procedural risk, but it is associated with long procedure times, extensive radiation exposure from fluoroscopy, implantation failure and lead dislodgement from the left ventricle. Two of the major difficulties of the transvenous approach are the small number of coronary vein branches adjacent to an appropriate left ventricle wall and variation in coronary vein anatomy among patients. Ideally, coronary venous morphology should be assessed non-invasively prior to a CRT procedure to determine whether epicardial or transvenous lead placement would be more appropriate for a particular patient.
Currently, two modalities are used for imaging of coronary venous anatomy: X-ray fluoroscopy and multi-detector computed tomography (MDCT). Invasive coronary X-ray venography is routinely performed immediately prior to placement of a left ventricle pacemaker lead. A balloon-tipped catheter is inserted into the coronary sinus, followed by injection of a contrast agent after balloon occlusion of the coronary sinus close to its ostium. MDCT can also be used to obtain detailed noninvasive imaging of the coronary veins. The major disadvantage of MDCT is the radiation dose received in addition to the already significant dose that the patient later receives during the interventional procedure. In addition, MDCT coronary venography requires administration of a nephrotoxic iodinated contrast to a population in which renal dysfunction is common.